Cisterns & Rain Barrels

A rain barrel is a storage container connected to a downspout that captures stormwater runoff from the roof. The stored water can be used to water non-edible plants or for outdoor cleaning.

Surface cisterns

Cisterns and rain barrels are containers that capture and store stormwater for non-potable, (or untreated) beneficial reuse, such as irrigation, toilet flushing or industrial uses. Stormwater runoff is typically conveyed from roof areas to the rain barrels or cisterns through roof gutters, downspouts, drains and/or pipes. Screens on gutters and downspouts filter large sediment and debris before it enters the rain barrel or cistern. First flush diverters are used in some systems to capture debris and pollutants within the first few gallons of stormwater runoff during a rainstorm. Some systems may be designed to detain and slowly release water back to the existing sewer system via an orifice or valve.

Rain barrels are typically located adjacent to buildings at single downspout locations. Cisterns may be located above or below ground and usually receive stormwater runoff from multiple downspouts or conveyance manifold systems.

Illustration of a residential rain barrel
Diagram of a surface cistern with a first flush diverter
Diagram of a subsurface cistern
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